Conventionally, as disclosed in International Publication Pamphlet No. 2006-123448, a technique of reducing the number of files that are opened involves handling the files in a compressed format and strictly selecting files that have a potential of satisfying search conditions. In general, concerning file searches, the use of archives is accepted to be effective against the problems of fragmentation of storage areas and increased storage size, problems occurring because the number of times opening processes are executed increases and file management is executed for each sector.
However, with the archives above, the computation of a compression parameter is necessary because files are respectively compressed using different compression parameters. Consequently, a problem has arisen in that the time necessary for the opening processes increases overall. With the technique disclosed in International Publication Pamphlet No. 2006-123448 and with archives, a problem has arisen in that the percentage of the files for which the opening processes are performed drastically increases as the number of files to be searched increases. Particularly, for large-scale dictionaries, opening processes accounts for 20 to 30% of the entire file processing and consequently, a problem has arisen in that this becomes a factor in reducing the speed of a full text search. In addition, a problem has arisen in that 13 comparisons are necessary in a binary search to identify a designated file among approximately 5,000 files. Furthermore, fragmentation of the disc area occurs because file management is executed for each sector, arising in a problem of the storage size increasing.
Meanwhile, for a search in a dictionary on a system including a single server that includes a large-capacity main storage memory, the dictionary is divided into numerous files and numerous disc areas, requiring a very long time for opening processes and reading processes to cause the dictionary to reside in a cache, and fragmentation of the storage area occurs in the cache resulting in a problem of the storage size increasing.
In many dictionary searches using grid computing, the entire search process is affected when a search process of a grid computer is delayed causing reduced search efficiency.